Module operation – Rockwell Automation T7444 ICS Regent+Plus AC Digital Output Module 110VAC User Manual
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AC Digital Output Module (T7444)
 
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Industrial Control Services
Module Operation
A block diagram of a typical 110 VAC digital output module is 
shown in Figure 1. 
The processor modules send triplicated write data commands 
to the output module over the I/O Safetybus. The processors’ 
addressing data and data write commands are voted by the 
module (preventing I/O Safetybus failures upstream from the 
module from affecting module operation). The voted result is 
then passed to the I/O bus interface logic. 
Figure 1. Block Diagram of 110 VAC Digital Output Module.
The voted output data from the I/O bus interface logic is then 
used to drive the output circuits. Zero crossing turn-on 
TRIAC drivers are used to convert the logic level output drive 
signals to switch 110 VAC power to load devices. 
When the output is logically turned on, the field device is 
energized, and when the output is logically turned off, the 
field device is de-energized.